For years cancer
survivors have worried about, joked about, and been frustrated by the mental
cloudiness they sometimes notice before, during, and after cancer treatment.
Even though its exact cause isn’t always known, this mental fog is commonly
called chemo brain. Patients have been aware of chemo brain for some
time, but only recently have studies been done that could help to explain it.

Doctors have known for
years that radiation treatment to the brain can cause thinking and memory
problems. Recently, they have found that chemo is linked to some of the same
kinds of problems. (To read more about radiation and its effects, see Understanding Radiation Therapy: A
Guide for Patients and Families.) Research shows that some
cancer drugs can cause certain kinds of changes in the brain. But it also shows
that chemo and radiation aren’t the only things that can cause thinking and
memory problems in people with cancer.

Though the brain usually
recovers over time, the sometimes vague yet distressing mental changes cancer
patients notice are real, not imagined. They might last a short time, or they
might go on for years. These changes can make people unable to go back to their
school, work, or social activities, or make it so that it takes a lot of mental
effort to do so. Chemo brain changes affect everyday life for many people, and
more research is needed to help prevent and cope with them.

What is chemo brain?

Here are just a few
examples of what patients call chemo brain:

Forgetting things that they usually have no trouble
recalling (memory lapses).

Trouble concentrating (they can’t focus on what
they’re doing, have a short attention span, may “space out”).

Trouble remembering common words (unable to find the
right words to finish a sentence).

Doctors and researchers
call chemo brain “mild cognitive impairment.” Most define it as being unable to
remember certain things and having trouble finishing tasks or learning new
skills. But some doctors call it chemo brain only if it doesn’t go away or get
better over time. How long it lasts is a major factor in how much it affects a
person’s life.

For most people, brain
effects happen quickly and only last a short time. Others have long-term mental
changes. Usually the changes that patients notice are very subtle, and others
around them may not even notice any changes at all. Still, the people who are
having problems are well aware of the differences in their thinking. Many
people don’t tell their cancer care team about this problem until it affects
their everyday life.

For someone who has lost
some brain function, even short-term problems with thinking and memory can be
scary. Some people may have trouble remembering simple things, like closing
doors or turning off lights. Others may notice that their brain doesn’t work as
quickly as it used to. These kinds of brain problems can cause trouble at work
and at home. People who notice problems with their thinking may feel even more
upset if their doctors blame it on aging or act like it’s nothing to worry
about. It’s distressing to wonder if you’ll ever be able to do your job again,
or if you’ll get lost on the way to a place you’ve been to dozens of times.

Brain problems
are hard to study.

Clearly, we need to know
more about chemo brain. But there are certain issues that make brain problems
hard to study. For instance, researchers sometimes use different tests to
measure the problems with thinking and memory, so the results may not compare
well with each other. Some people report changes that are so mild that their
brain tests look normal and doctors don’t have a good way to measure the
changes. One study even noted that changes like this are reported by people
with cancer who didn’t get chemo. This may mean the tests used in the study
weren’t sensitive enough to pick up smaller changes. It also suggests that
something other than chemo might have caused the problems. Still, chemo is one
of the causes of brain problems in some people with cancer. Many of these
people have brain function problems that are directly related to cancer or its
treatment, and most of these problems do show up on testing.

There are also
differences in when certain kinds of brain problems happen. Some researchers
have tested brain function a few weeks after treatment, others months or even
years later. If the problem only lasts a few weeks with no long-term changes,
late testing can miss it. If the changes last more than a year but the testing
stops after 6 months, no one knows how long they last. Beyond the chemo brain
symptoms that start during and just after treatment, it is clear that there are
some cases where brain symptoms start and even get worse after treatment is
over. Many cancer treatments, including certain kinds of chemo and radiation,
can cause short-term, long-term, and delayed problems.

Another timing problem
in studying chemo brain is that most studies didn’t test the patients before
treatment to compare to results after treatment. In studies that did tests
before treatment, some people were seen to have brain function problems before
treatment was even started. So it’s possible that the cancer itself causes some
of the problems, or that some other related problem caused brain function to
decline. Studies are needed that test people before the treatment and then follow
up to look for changes over time.

Differences in how chemo
brain is defined can also make it hard to get a handle on how often it happens.
There is a wide range of estimates of how many people get chemo brain. One
expert noted that, among people who get chemo, between 15% and 70% have brain
problems. Another expert put the upper limit of the range at 50%. So based on
these numbers, the risk of chemo brain (for people who get chemo) can be higher
than 1 out of 2 or as low as 1 in 6. This may not take into account people with
brain or thinking problems that may be caused by their cancer, radiation, or
other causes.

When it starts, how long
it lasts, and how much trouble it causes can vary a lot. So the term “chemo
brain” is not completely accurate. Still, it’s what most people call it right
now.

What causes brain problems during cancer treatment?

Studies suggest that
there may be more than one cause of chemo brain, especially for the short-term
symptoms. Some people with cancer have very real brain problems even though
they have not had chemo. Still others notice problems when getting hormone
treatments, such as estrogen blockers or androgen deprivation therapy
(treatments to lower testosterone levels). For some, problems start after
surgery. Along with chemo, many different problems can worsen brain function.

For instance, brain
problems could be caused or worsened by any one or any combination of these
factors:

The cancer itself

Other drugs used as part of treatment (such as
steroids, anti-nausea, drugs used for surgery, or pain medicines)

Low blood counts

Sleep problems

Infection

Tiredness (fatigue)

Hormone changes or hormone treatments

Other illnesses, such as diabetes or high blood
pressure

Nutritional deficiencies

Patient age

Depression

Stress, anxiety, or other emotional pressure

Most of these cause
short-term problems, and get better as the underlying problem is treated or
goes away. A few, such as depression, can cause long-lasting brain problems
unless the cause is treated.

So far, there is no
known way to prevent chemo brain. For some people, treating their cancer will
mean trouble with thinking, memory, planning, and word finding.

Studies of
brain problems related to cancer and its treatment

Imaging tests have shown
that in some patients, the parts of the brain that deal with memory, planning,
putting thoughts into action, monitoring thought processes and behavior, and
inhibition are smaller after chemotherapy. In some studies, these problems were
more common in those who got high-dose chemo (such as chemo used for stem cell
or bone marrow transplant). But a 2009 study of people who were tested before
stem cell transplant noted that some problems had started before the transplant
was done, and that memory greatly improved over the next 18 months. At that
time some still had trouble with slower reaction times and fine muscle
coordination, but other functions were better. In another series of studies,
brain problems that were present 2 years after treatment were much better 4
years after treatment.

A 2011 study looked at
patients who had a stem cell transplant from another person, which involves
both high-dose chemo and immune-suppressing drugs. The researchers tested these
patients early then observed them for 5 years after the transplant. Although
their thinking problems had improved after a year, more than 40% still had mild
brain problems after 5 years. The patients had improved in all other areas
tested, but they were still somewhat low on hand speed and dexterity as well as
word recall.

Pictures of the brain
have shown lower resting brain activity in breast cancer survivors treated with
chemo when compared with those who were not treated with chemo. These changes
were still seen on scans of some women 5 to 10 years after treatment stopped. And
during memory testing, these women had to call on and use larger areas of their
brains than women who had not gotten chemo.

It’s not all related to
chemo and radiation, though. A small 2012 study looked at women after breast
cancer surgery, before any other treatment was given. When tested, about 1 in 4
showed problems with word skills and about 1 in 7 had memory issues. Although
surgery, surgical drugs, or other factors may have had some effect, the women
who reported worse brain problems also reported higher stress levels.

In people with brain
problems, tests of memory usually show the person is slow to learn new things,
and they take longer to recall what they know. Response or reaction times slow
down; attention and concentration often suffer. Most often, tests find that the
person with chemo brain has more trouble in using recalled information
(executive function), and in using language.

More studies are being
done to try to better understand chemo brain. What is known for sure is that
brain slowdown is a real problem that affects both men and women. Most of these
people will notice that the problems get better over time. But others will have
to learn ways to deal with brain problems that don’t go away.

What can I do to manage brain problems?

Day-to-day
coping

Experts have been
studying memory for a long time. There are many resources that might help you
sharpen your mental abilities and manage the problems that might come with
chemo brain. Some things that you can do are:

Use a detailed daily planner. Keeping everything in
one place makes it easier to find the reminders you may need. Serious
planner users keep track of their appointments and schedules, “to do”
lists, important dates, websites, phone numbers and addresses, meeting
notes, and even movies they’d like to see or books they’d like to read.

Exercise your brain. Take a class, do word puzzles,
or learn a new language.

Get enough rest and sleep.

Exercise your body. Regular physical activity is not
only good for your body, but also improves your mood, makes you feel more
alert, and decreases tiredness (fatigue).

Eat your veggies. Studies have shown that eating
more vegetables is linked to keeping brain power as people age.

Set up and follow routines. Pick a certain place for
commonly lost objects and put them there each time. Try to keep the same
daily schedule.

Don’t try to multi-task. Focus on one thing at a
time.

Ask for help when you need it. Friends and loved
ones can help with daily tasks to cut down on distractions and help you
save mental energy.

Track your memory problems. Keep a diary of when you
notice problems and the events that are going on at the time. Medicines
taken, time of day, and the situation you are in might help you figure out
what affects your memory. Keeping track of when the problems are most
noticeable can also help you prepare. You’ll know to avoid planning
important conversations or appointments during those times. This will also
be useful when you talk with your doctor about these problems.

Try not to focus on how much these symptoms bother
you. Accepting the problem will help you deal with it. As many patients
have noted, being able to laugh about things you can’t control can help
you cope. And remember, you probably notice your problems much more than
others do. Sometimes we all have to laugh about forgetting to take the
grocery list with us to the store.

Telling others

Another thing you can do
to better manage chemo brain is tell family, friends, and your health care team
about it. Let them know what you are going through. You may feel relieved once
you tell people about the problems you sometimes have with your memory or
thinking.

You are not stupid or
crazy—you just have a side effect that you have to learn to manage. Even though
this is not a change that is easy to see, like hair loss or skin changes, your
family and friends may have noticed some things and may even have some helpful
suggestions. For instance, your partner may notice that when you are rushed,
you have more trouble finding things.

Tell your loved ones
what they can do to help. Their support and understanding can help you relax
and make it easier for you to focus and process information.

Talk with your
doctor or cancer care team

If brain problems cause you trouble at work, you may need
to talk with your doctor to try and pinpoint what is causing your brain fog and
what can be done about it. This is especially important for people whose
problem lasts for more than a year and keeps causing trouble in their daily
lives.

It helps a lot if you have a diary or log of the
situations you have trouble with. It also helps to know some of the things that
make the problem worse or better. For instance, are they worse in the morning
or evening? Do you have more trouble when you are hungry or tired? Does it help
to nap, walk, or have a snack? Your doctor will want to know when the problems
started and how they affect your daily life.

Write down questions about the problems you have to
talk over with your doctor. Take them to your appointment along with your
memory tracking log. Ask what may be causing the problems, and find out if
there’s anything the doctor can offer to help you.

Bring a list of all the medicines you take,
including herbs, vitamins, supplements, and those you take on an “as
needed” basis.

Take a friend or family member with you to help you
keep track of what was said during the visit. They can also describe the
changes they see if the doctor wants a different viewpoint of how your
brain problems are affecting you.

If your memory and thinking problems keep causing
trouble in your daily life, ask your doctor if you might be helped by a
specialist such as a neuropsychologist. These professionals can test you
and may recommend ways to help you better handle the problems.

You may need to visit a
larger hospital or cancer care center to find neurologists, psychologists, or
neuropsychologists who are experts on testing brain function, including chemo
brain. Ask if you can get a referral to one of these specialists who can help
you learn the scope of your problem and work with you on ways to manage it.
You’ll want to find out what your insurance will cover before you start.

Can brain problems be prevented?

The causes of brain
problems related to cancer and its treatment are still being studied, and at
this time there is no known way to prevent them. Chemo brain seems to happen
more often with high doses of chemo, and is more likely if the brain is also
treated with radiation. But because chemo brain is usually mild and most often
goes away in time, chemo that is proven to work against the cancer should not
be changed to try to prevent this side effect.

What’s being done about chemo brain?

Now that chemo brain has
clearly been linked to cancer and its treatment, studies are being done to
learn more about it. Some studies are looking to find out which chemo drugs and
other treatments are more closely linked to chemo brain. Researchers are also
looking at possible ways to prevent brain problems. For instance, certain drugs
are being looked at to protect the brain, but these have yet to be tested in
humans.

Researchers are studying
other aspects of cancer treatment that may lead to long-term mental changes,
too. For example, they are looking at the types and doses of chemo the patients
had, anemia, other cancer-related symptoms (like tiredness), and genetic
differences among people to see if these factors are linked to a higher risk of
brain problems.

Doctors are also
studying ways to help survivors who are still having trouble thinking.

Future
directions

Looking at how
brain problems happen

Studies have shown clear
evidence of nerve damage from at least some forms of chemotherapy. But studies
of the effects of chemo drugs on brain cells are rare. Special imaging tests
must be used to help pinpoint areas of increased and decreased activity in the
brain. This is a focus of ongoing research. Scientists must find out which
nerve cells or brain cells are at risk during cancer treatment to develop ways
to reduce damage, save brain function, and maintain the quality of life in
long-term survivors.

So far, early studies in
the lab and in animals suggest that certain chemo drugs may harm some nerve
cells even after the drug is stopped. Again, more research is needed to see if
this happens in humans, too.

There is more concern about
chemo brain today because cancer treatment studies have shown better outcomes
using more aggressive, high-dose drug schedules. Newer targeted drugs affect
certain pathways that are part of nerve cell formation and stem cell function,
which also is a cause for concern. Learning which nerve cells are affected may
help scientists test new drugs for this side effect.

Protecting the
brain

Cancer experts are
looking into treatment options that may protect the brain from chemo side
effects. Targeted drugs that focus on the cancer cells and spare normal cells,
such as brain and nerve cells are being studied.

Treating brain
problems

Researchers are looking
at medicines that are now used for problems like depression, attention-deficit
hyperactivity disorder (ADHD), Alzheimer disease, and dementia. These might
serve as possible treatments for chemo brain that doesn’t get better, but more
testing is needed.

Looking for
other links to brain problems

Genetic differences that
may make some people more likely to have symptoms of brain problems are being
explored. One particular gene, called APOE, is being looked at closely.
Research has shown that a version of this gene, called E4, is linked to
Alzheimer disease. When E4 is present, there is an increased chance of thinking
problems after traumatic brain injury, too. Studies are being done to find out
if people who have the E4 gene and get chemotherapy have a higher risk of
developing long-term chemo brain.

Recognizing that chemo
brain can be a treatment side effect was the first step. Doctors and
researchers are now trying to measure how exactly it affects patients’ brains
and cause changes. This important information can help them find ways to not
only treat brain problems, but in the future, help to prevent them. Clinical
trials are going on, and many more are needed.

Chemotherapy saves lives, but new
studies—including research led by coauthor Dr. Dan Silverman—reveal that the
agents used to kill cancer cells may also impair normal brain function. Even
years after treatment, patients report problems with memory, concentrating,
multitasking, and word retrieval. As one person put it, “I’ve lost my edge.” If
you’ve undergone chemotherapy, perhaps you’re among those who’ve had trouble
following the thread of a conversation or feel “less than” who you once were.
Until recently, oncologists often discounted or trivialized “chemo brain.” Now,
argue Silverman and Idelle Davidson, there is plenty of evidence to the
contrary; thankfully, you can rest assured that you’re not alone in feeling
this way—and that you can do something about it. Calling on cutting-edge
scientific research and the inspiring stories of survivors (including
Davidson’s own experiences with chemotherapy and its effects), this
groundbreaking book will forever change how you think about your brain after
chemo. Perhaps most important, it offers much-needed strategies to improve
memory and focus, and an invaluable nine-step program to help keep your brain
sharp. Your Brain after Chemo gives you the coping skills to move on with your
life.